Unilateral inferior rectus hypoplasia in a child with Axenfeld-Rieger syndrome

A 6-year-old boy with Axenfeld-Rieger syndrome presented with exotropia and a right hypertropia with limited depression. Computed tomography revealed hypoplasia of the right inferior rectus muscle. Forced duction testing was notable for a tight right superior rectus muscle. A superior rectus muscle recession reduced the primary position hypertropia but did not improve the patient's downgaze. To our knowledge, unilateral inferior rectus muscle hypoplasia has not been described previously in a patient with Axenfeld-Rieger syndrome.